Cnormal to the plane of the paper and coming out of the plane of the paper
c
(c)
Using right hand rule, direction of magnetic force can be found. It acts outward from the plane of paper in given case.
To avoid deflection of electron, electric field must be applied normal to the plane of paper ($XOY$-plane in diagrams) and pointing outward.
Magnitude of electric field applied is such that $F_m=F_e$
